code: def test_wca_raining_process():
      search_space = search.SearchSpace(
          n_agents=10,
          n_variables=2,
          lower_bound=[0, 0],
          upper_bound=[10, 10],
      )
  
      new_wca = wca.WCA()
      new_wca.compile(search_space)
      new_wca.flows[0] = 5
  
      new_wca.d_max = 100
      new_wca._raining_process(
          search_space.agents, search_space.best_agent
      )
  
file_path: opytimizer/tests/opytimizer/optimizers/science/test_wca.py
imports: import numpy
  from opytimizer.optimizers.science import wca
  from opytimizer.spaces import search
label_desc: Use image node_id 5 for calling a global function with example usage: test_wca_raining_process() without return types